The present invention relates to devices for dispensing pasty substances, such as ice creams for example, that is connectable to the machines that make the said substances.
More particularly, the invention relates to a piston device for dispensing ice creams in predetermined quantities, which device is connectable to the closing door of the freezing chamber of an ice cream making machine, preferably a soft ice cream making machine of the xe2x80x9cself-servicexe2x80x9d type operated automatically by coins or tokens.
Ice cream dispensers are known consisting of a dosing piston device (see for example Austrian Patent No. 257332 of 14.9.1965) that basically comprises a cylinder containing an axially sliding expulsion piston and a counter-piston, between which a measuring chamber is formed when the expulsion piston is raised, this chamber being filled with the ice cream coming from the freezing chamber of an ice cream making machine, after which both pistons are slid axially with the volume of ice cream held between them until the counter-piston meets a stop, such that further movement of the expulsion piston expels the volume of ice cream contained between the piston and the counter-piston through a dispensing port.
These known devices are mechanically complex, are difficult to adjust when it is wished to change the amount of product dispensed, and above all are difficult to maintain and to clean.
The object of the present invention is therefore to provide a piston device for dispensing controlled amounts of pasty substances, particularly ice creams, that can be connected to the door of the freezing chamber of an ice cream making machine, in such a way as to overcome the drawbacks and disadvantages of known piston devices that deliver metered amounts of substance.
In accordance with one feature of the present invention, the dispensing device delivers metered amounts of substance comprises a cylindrical closing element mounted rotatably about its axis in a mating cradle support, recessed diametrically into which cylindrical closing element is a cylindrical housing (hereinafter abbreviated to xe2x80x9ccylinderxe2x80x9d) that is closed at the bottom by a wall containing a hole, while a piston slides axially inside the said cylinder, and in which the said cradle support contains a communicating hole leading to the freezing chamber of the ice cream making machine, so that in one angular position of the said cylindrical closing element the said hole of the support is lined up with the hole of the bottom wall of the said cylinder, while in a second angular position of the said cylindrical closing element the said hole of the bottom wall of the cylinder is lined up with a dispensing hole provided in the said cradle support, while the side wall of the said cylindrical closing element is provided with an elongate passage which in a third position of the said cylindrical closing element connects together the feed hole and the dispensing hole of the support, bypassing the said cylinder.